CN112943732B - Overflow valve with different opening and closing pressures - Google Patents
Overflow valve with different opening and closing pressures Download PDFInfo
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- CN112943732B CN112943732B CN202110312183.0A CN202110312183A CN112943732B CN 112943732 B CN112943732 B CN 112943732B CN 202110312183 A CN202110312183 A CN 202110312183A CN 112943732 B CN112943732 B CN 112943732B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B13/00—Details of servomotor systems ; Valves for servomotor systems
- F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
- F15B13/021—Valves for interconnecting the fluid chambers of an actuator
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Abstract
The embodiment of the invention provides an overflow valve with different opening and closing pressures, which comprises a main valve, a pilot valve and a hydraulic control one-way valve; the main valve is connected between the main pipeline and the oil return tank through a connecting oil way; the main valve has an opening pressure P1; a connecting oil path between the main valve and the oil return tank is provided with a hydraulic control one-way valve, and the one-way conduction direction of the hydraulic control one-way valve is from the oil return tank to the main valve; the pilot valve is provided with a low-pressure output state and a high-pressure output state, and the switching pressure P2 for switching from the high-pressure output state to the low-pressure output state is less than the opening pressure P1; the pilot valve is connected with the hydraulic control one-way valve through the connecting oil way, the hydraulic control one-way valve is opened in a high-pressure output state, and the hydraulic control one-way valve is communicated from the oil return tank to the main valve in a one-way mode in a low-pressure output state. The pressure difference of the opening and the closing of the overflow valve can be realized, when the system pressure is higher than the safety pressure (opening pressure P1), the overflow occurs, and then the system pressure is reduced to the set pressure (switching pressure P2 is smaller than P1) and then the overflow valve is closed, so that the overflow valve has a better safety protection effect.
Description
Technical Field
The embodiment of the invention relates to the technical field of hydraulic valves, in particular to an overflow valve with different opening and closing pressures.
Background
The overflow valve plays a safety protection role in the hydraulic system. When the system pressure exceeds a set value, the overflow valve is opened to drain pressure oil, so that the system pressure does not exceed the set value, and the system is prevented from accidents caused by overhigh pressure.
Most of existing overflow valves can only set opening pressure, when the pressure received by the overflow valve exceeds the opening pressure, the overflow valve is opened, the closing pressure can only be set to be the same as the opening pressure, and when the pressure received by the overflow valve is lower than the closing pressure, the overflow valve is closed. However, in the actual production application, the pipeline of some hydraulic system pressure relief devices is too long (the pipeline can generate pressure drop), so that the pressure at the pressure relief position (namely the pressure received by the overflow valve) can be lower than the pressure in the main pipeline of the hydraulic system, and if the closing pressure of the overflow valve is the same as the opening pressure, the condition that the overflow valve is already closed when the pressure of the main pipeline is not reduced to the safety pressure can be generated, so that the hydraulic system can bear the high-pressure hazard.
Disclosure of Invention
In order to solve or at least alleviate at least one of the above technical problems, embodiments of the present invention provide an overflow valve with different opening and closing pressures, so that the closing pressure is smaller than the opening pressure, and a better safety protection effect is achieved.
In one aspect of an embodiment of the present invention, an overflow valve having different opening and closing pressures includes: the pilot valve is connected with the main valve;
the main valve is connected between the main pipeline and the oil return tank through a connecting oil way; said main valve having an opening pressure P1;
the hydraulic control one-way valve is arranged on a connecting oil path between the main valve and the oil return tank, and the one-way conduction direction of the hydraulic control one-way valve is from the oil return tank to the main valve;
the pilot valve is provided with a low-pressure output state and a high-pressure output state, and the switching pressure P2 for switching from the high-pressure output state to the low-pressure output state is less than the opening pressure P1; the pilot valve is connected with the hydraulic control one-way valve through a connecting oil way, the hydraulic control one-way valve is opened in a high-pressure output state, and the hydraulic control one-way valve is communicated from the oil return tank to the main valve in a one-way mode in a low-pressure output state.
In one implementation of an embodiment of the present invention, the main valve includes a first valve spool, a valve sleeve, a piston, and a first spring; the first valve core is fixedly connected with the piston; the first valve core is positioned in a main cavity formed by the valve sleeve, and the main cavity is connected between a main pipeline and an oil return box through a connecting oil way; the piston and the valve sleeve form a piston cavity and a spring cavity which are mutually isolated; the first spring is disposed in the spring chamber, the first spring applies a force to the first valve spool to close the main valve, and a pressure required to open the main valve against the first spring resistance is the main valve opening pressure P1.
According to one implementation mode of the embodiment of the invention, the main cavity is provided with a main oil inlet and a main oil outlet, the main oil inlet is connected with the main pipeline through a connecting oil path, and the main oil outlet is connected with the oil return tank through a connecting oil path; the spring cavity is connected with the oil return box through a connecting oil way.
In an implementation manner of the embodiment of the present invention, the hydraulic control check valve is disposed in a connection oil path between the piston cavity and the oil return tank, the hydraulic control check valve is provided with a first hydraulic control port, the check valve is opened when the first hydraulic control port is connected to the oil path through the pilot valve, and the first hydraulic control port is unidirectionally conducted when connected to the oil return tank through the pilot valve.
In an implementation manner of the embodiment of the present invention, the pilot valve adopts a two-position three-way valve, and includes a second hydraulic control port, a first input port, a second input port, an output port, and a second valve core; the second hydraulic control port and the first input port are connected with the main pipeline through a connecting oil way; the second input port is connected with the oil return tank through a connecting oil way; the output port is connected with a first hydraulic control port of the hydraulic control one-way valve through a connecting oil way.
In one embodiment of the present invention, when the second valve core is in the first valve position, the first input port and the output port are communicated, and the second valve core is in a high-pressure output state; when the second valve core is at the second valve position, the second input port is communicated with the output port, and the second valve core is in a low-pressure output state.
In one embodiment of the present invention, the pilot valve is further provided with a second spring, and the second spring applies force to the second valve spool to keep the second valve spool at the first valve position; the pressure required to move the second valve spool from the first valve position to the second valve position against the second spring resistance is the switching pressure P2.
According to the overflow valve with different opening and closing pressures, the main valve is connected between the main pipeline and the oil return tank through the connecting oil way; the main valve has an opening pressure P1; a connecting oil path between the main valve and the oil return tank is provided with a hydraulic control one-way valve, and the one-way conduction direction of the hydraulic control one-way valve is from the oil return tank to the main valve; the pilot valve is provided with a low-pressure output state and a high-pressure output state, and the switching pressure P2 for switching from the high-pressure output state to the low-pressure output state is less than the opening pressure P1; the pilot valve is connected with the hydraulic control one-way valve through the connecting oil way, the hydraulic control one-way valve is opened in a high-pressure output state, and the hydraulic control one-way valve is communicated from the oil return tank to the main valve in a one-way mode in a low-pressure output state. The pressure difference of the opening and the closing of the overflow valve can be realized, when the system pressure is higher than the safety pressure (opening pressure P1), the overflow occurs, and then the system pressure is reduced to the set pressure (switching pressure P2, which is less than P1) and then the overflow valve is closed, so that the overflow valve has a better safety protection effect.
Drawings
The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the principles of the embodiments of the invention.
Fig. 1 is a hydraulic schematic diagram of an exemplary structure of a relief valve according to an embodiment of the present invention.
Fig. 2 is a pressure-spool displacement diagram of a relief valve according to an embodiment of the present invention.
Fig. 3 is a pressure-flow diagram of a relief valve according to an embodiment of the present invention.
Description of reference numerals:
1-a main valve; 11-a first valve spool; 12-a piston; 13-a valve housing; 14-a first spring; 2-a pilot valve; 21-a second spring; 3-a hydraulic control one-way valve; 4-oil return tank.
Detailed Description
The embodiments of the present invention will be described in further detail with reference to the drawings and the following description. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are given by way of illustration only. It should be noted that, for convenience of description, only the portions related to the embodiments of the present invention are shown in the drawings.
It should be noted that, in the embodiments of the present invention, features in the embodiments may be combined with each other without conflict. Embodiments of the present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.
The embodiment of the invention provides an overflow valve with different opening and closing pressures, so that the closing pressure is smaller than the opening pressure, and the overflow valve has a better safety protection effect. The following description is presented to illustrate various embodiments and to best explain the principles and concepts of the embodiments.
In accordance with one aspect of an embodiment of the present invention, reference is made to a hydraulic schematic for one exemplary configuration of a relief valve as shown in FIG. 1. The overflow valve with different opening and closing pressures is arranged in an overflow bypass of a main pipeline of a hydraulic system and used for protecting a fluid pipeline within a safe pressure range, and comprises a main valve 1, a pilot valve 2 and a hydraulic control one-way valve 3.
The main valve 1 is connected between the main pipeline and the oil return tank 4 through a connecting oil path, and the main valve 1 is used for communicating or cutting off the main pipeline and the oil return tank 4 so as to control the overflow function of the hydraulic system. The main valve 1 has a cracking pressure P1, and the main valve 1 opens for overflow only if the pressure in the main line is greater than the cracking pressure P1.
The connecting oil path between the main valve 1 and the oil return tank 4 is provided with a hydraulic control one-way valve 3, and the one-way conduction direction of the hydraulic control one-way valve 3 is from the oil return tank 4 to the main valve 1. The pilot operated check valve 3 is a check valve that changes its conducting state under the control of hydraulic pressure, and has a conducting state and a check valve state. When the pilot-controlled check valve 3 is in a conducting state, the main valve 1 and the oil return tank 4 are normally communicated, and the main valve 1 can be normally opened and closed. When the pilot-controlled check valve 3 is in the check valve state, the oil path between the main valve 1 and the return tank 4 can only be communicated from the return tank 4 to the main valve 1 in one direction, so the oil-sucking normal main valve 1 can be normally opened, but the return oil is locked and can not be closed.
The pilot valve 2 is provided with a low-pressure output state and a high-pressure output state, the pilot valve 2 is connected with the hydraulic control one-way valve 3 through a connecting oil way, the hydraulic control one-way valve 3 is opened in the high-pressure output state, and the hydraulic control one-way valve 3 is communicated with the main valve 1 from the oil return tank 4 in a one-way mode in the low-pressure output state. The pilot valve 2 is used for controlling the state of the pilot-controlled check valve 3, and the low-pressure output state and the high-pressure output state are relative, and the pressure which can enable the pilot-controlled check valve 3 to be in the check valve state can be called as the low-pressure output state; the pressure that can make the pilot operated check valve 3 be in the conducting state can all be called high pressure output state to under normal condition, pilot valve 2 all is in high pressure conducting state, thereby pilot operated check valve 3 is in the conducting state. The state of the pilot valve 2 can be switched to different states according to the change of the main line pressure, when the main line pressure is within a normal range, the pilot valve 2 is in an initial normal state, i.e., a high-pressure output state, the pressure required for switching from the high-pressure output state to a low-pressure output state is a switching pressure P2, and the switching pressure P2 is less than the opening pressure P1. That is, when the main line pressure exceeds the switching pressure P2, the pilot valve 2 is switched to the low pressure output state, and the pilot operated check valve 3 is in the check valve state.
According to the overflow valve with different opening and closing pressures, the main valve 1 is connected between the main pipeline and the oil return tank 4 through the connecting oil way; main valve 1 has an opening pressure P1; a connecting oil path between the main valve 1 and the oil return tank 4 is provided with a hydraulic control one-way valve 3, and the one-way conduction direction of the hydraulic control one-way valve 3 is from the oil return tank 4 to the main valve 1; the pilot valve 2 is provided with a low-pressure output state and a high-pressure output state, and the switching pressure P2 for switching from the high-pressure output state to the low-pressure output state is less than the opening pressure P1; the pilot valve 2 is connected with the hydraulic control one-way valve 3 through a connecting oil way, the hydraulic control one-way valve 3 is opened in a high-pressure output state, and the hydraulic control one-way valve 3 is communicated with the main valve 1 from the oil return tank 4 in a one-way mode in a low-pressure output state. The pressure difference of the opening and the closing of the overflow valve can be realized, when the system pressure is higher than the safety pressure (opening pressure P1), the overflow occurs, and then the system pressure is reduced to the set pressure (switching pressure P2, which is less than P1) and then the overflow valve is closed, so that the overflow valve has a better safety protection effect.
Alternatively, the main valve 1 may include a first spool 11, a valve sleeve 13, a piston 12, and a first spring 14. The first valve core 11 is fixedly connected with the piston 12, the movement of the first valve core 11 is synchronous with the movement of the piston 12, and the first valve core 11 is driven to move by the forced movement of the piston 12, so that the opening and closing of the main valve 1 are realized. The first valve core 11 is positioned in a main cavity formed by the valve sleeve 13, and the main cavity is connected between a main pipeline and the oil return box 4 through a connecting oil way; the valve pocket 13 encloses a main cavity, optionally, the main cavity is provided with a main oil inlet and a main oil outlet, the main oil inlet is connected with the main pipeline through a connecting oil path, and the main oil outlet is connected with the oil return tank 4 through a connecting oil path. The first spool 11 is movable within the main chamber to close or open the main oil inlet. The piston 12 and the valve sleeve 13 form a piston cavity and a spring cavity which are isolated from each other; the valve housing 13 encloses a further chamber in addition to the main chamber, and the piston 12 is arranged in the further chamber, dividing the further chamber into a piston chamber (without a spring) and a spring chamber. The spring cavity is connected with the oil return tank 4 through a connecting oil path. The first spring 14 is disposed in the spring chamber, and the first spring 14 applies a force to the first valve spool 11, the force having a tendency to push the piston 12 and the first valve spool 11 toward the main inlet port of the main chamber, and the pressure required to open the main valve 1 against the resistance of the first spring 14 is the main valve 1 opening pressure P1. That is, in the normal operation state, the first spring 14 presses the first valve spool 11 against the oil inlet, the main valve 1 is closed, and only when the pressure of the main pipeline received by the main valve 1 is greater than the opening pressure P1 of the main valve 1, the main valve 1 is opened against the resistance of the first spring 14 to generate the overflow action.
Optionally, a hydraulic control one-way valve 3 is arranged in a connecting oil path between the piston cavity and the oil return tank 4, the hydraulic control one-way valve 3 is provided with a first hydraulic control port, the hydraulic control one-way valve 3 is opened when the first hydraulic control port is connected with the oil path through a pilot valve, and the hydraulic control one-way valve 3 is conducted in one way from the oil return tank 4 to the piston cavity when the first hydraulic control port is connected with the oil return tank through the pilot valve. The hydraulic control one-way valve 3 is used for changing the oil return state of the piston cavity, if the hydraulic control one-way valve 3 is opened, the piston cavity can normally absorb and return oil from the oil return tank 4, and if the hydraulic control one-way valve 3 is in a one-way conduction state, the piston cavity can only absorb oil from the oil return tank 4 but cannot return oil to the oil return tank 4, so that the piston 12 and the first valve core 11 cannot move towards the main oil inlet, and the main valve 1 keeps the opening state.
Optionally, the pilot valve 2 may adopt a two-position three-way valve, that is, there are two valve positions, and there are three connectors and one control port, and specifically include a second hydraulic control port, a first input port, a second input port, an output port, and a second valve core. The second hydraulic control port and the first input port are connected with the main pipeline through a connecting oil way and can receive the high pressure of the main pipeline; the second input port is connected with the oil return tank 4 through a connecting oil path and can receive the low pressure of the oil return tank 4; the output port is connected with a first hydraulic control port of the hydraulic control one-way valve 3 through a connecting oil path and is used for transmitting high pressure or low pressure to the hydraulic control one-way valve 3. The connection mode can form high pressure by means of the pressure of the main pipeline and output the high pressure to the hydraulic control one-way valve 3, a closed loop control loop between the pressure of the main pipeline and the state of the hydraulic control one-way valve 3 is formed, and the sensitivity to the pressure change of the main pipeline is increased.
Optionally, the pilot valve 2 has a first valve position and a second valve position, and when the second valve core is in the first valve position, the first input port is communicated with the output port, and transmits the high pressure of the main pipeline to the output port, and the pilot valve is in a high-pressure output state; when the second valve core is in the second valve position, the second input port is communicated with the output port, the low pressure of the oil return tank 4 is transmitted to the output port, and the second valve core is in a low-pressure output state.
Optionally, the pilot valve 2 is further provided with a second spring 21, and the second spring 21 applies a force to the second valve spool to keep the second valve spool at the first valve position, that is, in a normal state, the second valve spool is at the first valve position, and the pilot valve 2 is in a high-pressure output state. For example, the second spring 21 has one end abutting against the valve body/sleeve 13 and the other end abutting against the second valve spool, pushing the second valve spool to the first valve position, to the right in fig. 1. The pressure required to move the second spool from the first position to the second position against the resistance of the second spring 21 is the switching pressure P2. That is, the second valve spool is switched to the second valve position against the resistance of the second spring 21 only when the pressure of the main pipe is greater than the switching pressure P2, so that the pilot valve 2 becomes the low pressure output state. Since the switching pressure P2 is lower than the cracking pressure P1, the main valve 1 does not close even if the main line pressure is reduced to be lower than the cracking pressure P1, and the main valve 1 closes only if the main line pressure is reduced to be lower than the switching pressure P2, which increases the safety performance of the relief valve.
The operation of the relief valve according to the embodiment of the present invention will be described in detail below, and the following description of the left and right directions will be understood with reference to the directions shown in fig. 1 for the sake of simplicity of explanation.
Referring to the curve of the relief valve shown in fig. 2, the displacement x of the main spool changes with the pressure during the operation. In the process of increasing the main line pressure, when the main line pressure is less than the opening pressure P1, the first valve core 11 is kept stationary due to the pre-pressure action of the first spring 14; when the main line pressure is greater than the cracking pressure P1, the first valve spool 11 begins to move and reaches and maintains a maximum opening when the hydraulic pressure across the first valve spool 11 and the first spring 14 pressure equalize. In the process of reducing the pressure of the main pipeline, when the pressure of the main pipeline is greater than the switching pressure P2 and less than the opening pressure P1, the pilot valve 2 outputs low pressure, so that the pilot-controlled check valve 3 is in a check valve state, a spring cavity becomes a dead cavity, and the first valve core 11 is still kept still; when the pressure of the main pipeline is less than P2, the pilot valve 2 outputs high pressure, so that the pilot operated check valve 3 is in an open state, the spring cavity starts oil return, the first valve core 11 moves leftwards, and the main oil inlet is gradually closed.
Referring to the curve of the relief valve shown in fig. 3, the flow rate varies with pressure during operation. In the process of increasing the main line pressure, when the main line pressure is less than the cracking pressure P1, the first valve core 11 is not opened, so there is no flow; when the main line pressure is greater than the cracking pressure P1, the first valve spool 11 opens gradually, the opening increases gradually, and the flow rate increases gradually. In the process of reducing the pressure of the main pipeline, when the pressure of the main pipeline is greater than the switching pressure P2 and less than the opening pressure P1, due to the action of the hydraulic control one-way valve 3, the spring cavity is a dead cavity, the first valve core 11 cannot be closed, and at the moment, the load end still has flow; when the main line pressure is less than P2, the spring chamber can return oil normally, the first valve core 11 is closed gradually, then the flow rate is reduced continuously until it is 0, and the overflow is finished.
The working process of the overflow valve of the embodiment of the invention is as follows:
(1) when the system pressure Ps (i.e., the main line pressure) is lower than the switching pressure P2, the hydraulic pressure acting on the pilot valve 2 core is smaller than the set force of the second spring 21, the pilot valve 2 core is in the right position, and outputs high pressure, so that the pilot check valve 3 is in a fully open state; since the switching pressure P2 is lower than the opening pressure P1, the hydraulic pressure acting on the first valve spool 11 is lower than the set force of the first spring 14, the displacement x of the first valve spool 11 is 0, the main valve 1 is in the closed and non-oil-passage state, and the oil passage flow rate Q is 0.
(2) When the system pressure Ps is higher than the switching pressure P2 and lower than the opening pressure P1, the hydraulic pressure acting on the pilot valve 2 core is greater than the set force of the second spring 21, the pilot valve 2 core is in the left position, and the pilot valve outputs low pressure, so that the pilot check valve 3 is in a check valve state; at this time, the force acting on the first valve element 11 is still smaller than the set force of the first spring 14, the displacement x of the first valve element 11 is kept at 0, the main valve 1 is in the closed and non-oil-flow state, and the oil flow rate Q is 0.
(3) When the system pressure Ps is higher than the opening pressure P1, the pilot valve 2 core is in the left position, and outputs low pressure, so that the pilot-controlled check valve 3 is in a check valve state; the hydraulic pressure of the first valve core 11 is larger than the set force of the first spring 14, the piston cavity is replenished with oil through the hydraulic control one-way valve 3, and the main valve 1 is opened to feed oil, namely, the overflow is started.
(4) When the system pressure Ps is lower than the opening pressure P1 and higher than the switching pressure P2, the pilot valve 2 core is still at the left position, and outputs low pressure, so that the pilot-controlled check valve 3 is in a check valve state; the hydraulic pressure of the first valve core 11 is smaller than the set force of the first spring 14, but the piston cavity becomes a closed cavity because of the one-way valve, the main valve core can not move leftwards, and the main valve 1 is still in an open oil-passing state.
(5) When the system pressure Ps is lower than the switching pressure P2, the pilot valve 2 core is in the right position, and outputs high pressure, so that the pilot-controlled check valve 3 is in an open state; the hydraulic pressure of the first valve core 11 is smaller than the setting force of the first spring 14, the piston cavity is no longer a dead space due to full opening, the main valve core can move leftwards, the main valve 1 is closed, and the overflow is finished.
In the description herein, reference to the description of the terms "one embodiment/mode," "some embodiments/modes," "example," "specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment/mode or example is included in at least one embodiment/mode or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to be the same embodiment/mode or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments/modes or examples. Furthermore, the various embodiments/aspects or examples and features of the various embodiments/aspects or examples described in this specification can be combined and combined by one skilled in the art without conflicting therewith.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
It should be understood by those skilled in the art that the foregoing embodiments are merely for illustrating the embodiments of the present invention clearly and are not intended to limit the scope of the embodiments of the present invention. Other variations or modifications will occur to those skilled in the art based on the foregoing disclosure and are within the scope of the embodiments of the invention.
Claims (7)
1. The utility model provides an overflow valve with different pressures of opening and close which characterized in that includes: the pilot valve is connected with the main valve;
the main valve is connected between the main pipeline and the oil return tank through a connecting oil way; said main valve having an opening pressure P1;
the hydraulic control one-way valve is arranged on a connecting oil path between the main valve and the oil return tank, and the one-way conduction direction of the hydraulic control one-way valve is from the oil return tank to the main valve;
the pilot valve is provided with a low-pressure output state and a high-pressure output state, and the switching pressure P2 for switching from the high-pressure output state to the low-pressure output state is less than the opening pressure P1; the pilot valve is connected with the hydraulic control one-way valve through a connecting oil way, the hydraulic control one-way valve is opened in a high-pressure output state, and the hydraulic control one-way valve is communicated from the oil return tank to the main valve in a one-way mode in a low-pressure output state.
2. The excess flow valve with different opening and closing pressures of claim 1 wherein the main valve includes a first valve core, a valve sleeve, a piston and a first spring; the first valve core is fixedly connected with the piston; the first valve core is positioned in a main cavity formed by the valve sleeve, and the main cavity is connected between a main pipeline and an oil return box through a connecting oil way; the piston and the valve sleeve form a piston cavity and a spring cavity which are mutually isolated; the first spring is disposed in the spring chamber, the first spring applies a force to the first valve spool to close the main valve, and a pressure required to open the main valve against the first spring resistance is the main valve opening pressure P1.
3. The overflow valve with different opening and closing pressures as claimed in claim 2, wherein the main cavity is provided with a main oil inlet and a main oil outlet, the main oil inlet is connected with the main pipeline through a connecting oil path, and the main oil outlet is connected with the oil return tank through a connecting oil path; the spring cavity is connected with the oil return box through a connecting oil way.
4. The overflow valve with different opening and closing pressures as claimed in claim 3, wherein the connection oil path between the piston chamber and the oil return tank is provided with the hydraulic control one-way valve, the hydraulic control one-way valve is provided with a first hydraulic control port, the first hydraulic control port is opened when connected with the oil path through the pilot valve, and the first hydraulic control port is unidirectionally conducted when connected with the oil return tank through the pilot valve.
5. The overflow valve with different opening and closing pressures of claim 4, wherein the pilot valve adopts a two-position three-way valve which comprises a second hydraulic control port, a first input port, a second input port, an output port and a second valve core; the second hydraulic control port and the first input port are connected with the main pipeline through a connecting oil way; the second input port is connected with the oil return tank through a connecting oil way; the output port is connected with a first hydraulic control port of the hydraulic control one-way valve through a connecting oil way.
6. The overflow valve with different opening and closing pressures of claim 5, wherein when the second valve core is at the first valve position, the first input port and the output port are communicated and are in a high-pressure output state; when the second valve core is at the second valve position, the second input port is communicated with the output port, and the second valve core is in a low-pressure output state.
7. The overflow valve with different opening and closing pressures as claimed in claim 6, wherein the pilot valve is further provided with a second spring, and the second spring applies force to the second valve core to keep the second valve core at the first valve position; the pressure required to move the second valve spool from the first valve position to the second valve position against the second spring resistance is the switching pressure P2.
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| CN202110312183.0A CN112943732B (en) | 2021-03-24 | 2021-03-24 | Overflow valve with different opening and closing pressures |
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| CN202110312183.0A CN112943732B (en) | 2021-03-24 | 2021-03-24 | Overflow valve with different opening and closing pressures |
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| CN112943732B true CN112943732B (en) | 2022-05-17 |
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| CN206495848U (en) * | 2016-12-29 | 2017-09-15 | 上海华岛液压设备制造有限公司 | Redundancy-type electromagnetic relief valve |
| CN108561352A (en) * | 2018-04-09 | 2018-09-21 | 广西柳工机械股份有限公司 | Prefill valve and quarry tipper hydraulic system |
| CN110094187A (en) * | 2018-01-29 | 2019-08-06 | 中国石油化工股份有限公司 | One kind lifting water pumping gas production tubing string and system from energy ladder |
| CN210715334U (en) * | 2019-07-22 | 2020-06-09 | 深圳东风汽车有限公司 | Hydraulic system output device and garbage compressor hydraulic system adopting same |
| CN211231075U (en) * | 2019-12-27 | 2020-08-11 | 三一重机有限公司 | Overflow valve, pressure regulating device and excavator |
-
2021
- 2021-03-24 CN CN202110312183.0A patent/CN112943732B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3441853A1 (en) * | 1983-11-18 | 1985-05-30 | Kabushiki Kaisha Komatsu Seisakusho, Tokio/Tokyo | Device for controlling the hydraulic pressure for a hydraulically actuatable manual shift transmission |
| CN206495848U (en) * | 2016-12-29 | 2017-09-15 | 上海华岛液压设备制造有限公司 | Redundancy-type electromagnetic relief valve |
| CN110094187A (en) * | 2018-01-29 | 2019-08-06 | 中国石油化工股份有限公司 | One kind lifting water pumping gas production tubing string and system from energy ladder |
| CN108561352A (en) * | 2018-04-09 | 2018-09-21 | 广西柳工机械股份有限公司 | Prefill valve and quarry tipper hydraulic system |
| CN210715334U (en) * | 2019-07-22 | 2020-06-09 | 深圳东风汽车有限公司 | Hydraulic system output device and garbage compressor hydraulic system adopting same |
| CN211231075U (en) * | 2019-12-27 | 2020-08-11 | 三一重机有限公司 | Overflow valve, pressure regulating device and excavator |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112943732A (en) | 2021-06-11 |
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